[Skin slice used as a model for investigating acupuncture effects].

OBJECTIVE: To establish an acupoint-connective tissue model for studying the mechanism of acupuncture by using in vitro patch clamp technique in the rat skin slices. METHODS: The local connective tissue under the corium of "Housanli" (ST 36) area from SD rat was acutely and bluntly separated and fixed in a chamber filled with artificial incubation solution. Mast cells in the prepared connective tissue slice were labeled by toluidine blue (TB) or neutral red (NR). The whole-cell current of mast cells responding to pressure stimulation applied through a patch pipette was recorded in rat slices derived from acupoint ST 36 area by using in vitro patch-clamp technique. RESULTS: 1) After staining with TB and NR, the labeled mast cells were found to distribute in the extracellular matrix of the connective tissue samples, and their degranulation phenomenon could be seen clearly. 2) The whole-cell current of mast cells in response to mechanical stress stimulation was successfully recorded in the connective tissue slices of the rat acupoint ST 36 area. The cellular membrane currents increased evidently when pressure gradients of -30, -60 or -90 cmH2O were applied to the recorded mast cells. CONCLUSION: The connective tissue slice from the rat ST 36 area may be used as a model for investigating the peripheral mechanism of acupuncture by combining the microtechniques and electrophysiological techniques. The results obtained in this model prove for the first time by electrophysiology that the mast cells in the connective tissue are probably involved in the transduction process of the mechanical signal from acupuncture stimulation. This new model provides a base for investigating the characters of the cells, collagen fibers, proteoglycans, etc. and their interactions in the acupoint connective tissue in the future.

[Electroacupuncture alleviates complete Freund's adjuvant peripheral chronic inflammatory pain in mice].

OBJECTIVE: To probe into the law of acupuncture analgesic effect and specificities of acupoint action. METHODS: Adult male Kunming mice were randomly divided into a control group, a model group, a model plus electroacupuncture (EA) group and a model plus sham EA group. Chronic inflammatory pain model was prepared by injection of complete Freund's adjuvant (CFA) into right posterior foot, and paw withdrawing latency (PWL) induced by radiation heat was used as pain threshold index, and changes of PWL in all the groups were investigated. RESULTS: After modeling, PWL significantly shortened on the inflammatory side (P < 0.05); EA at bilateral "Zusanli" (ST 36) and "Kunlun" (BL 60) could significantly reverse the shortened PWL (P < 0.05), and this effect was prolonged along with increase of EA times, but in the sham EA group PWL did not significantly change; EA at bilateral "Shousanli" (LI 10) and Neiguan" (PC 6) could not reverse the shortened PWL (P > 0.05). CONCLUSION: Analgesic effect of EA is strengthened along with increase of EA times and shows specificity of acupoints to a certain extent.